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Dec
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awarded  Proofreader
Dec
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reviewed Approve mixing-function tag wiki
Dec
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reviewed Approve mixing-function tag wiki excerpt
Dec
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reviewed Approve avalanche tag wiki excerpt
Dec
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reviewed Approve avalanche tag wiki
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reviewed Approve Can you help me with this DES variant analysis?
Dec
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comment Rabin/RSA four possible messages?
Also, yes, the second part is just asking for the decryption algorithm. DrLecter's hint above should help with that too. Note that, for efficient decryption, you'll need to know the factors $p$ and $q$ of $N$.
Dec
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revised Rabin/RSA four possible messages?
copyedit, clean up TeX formatting
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revised Can you help me with this DES variant analysis?
copy comments to answer
Dec
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revised Find the key to a Vigenère cipher, given known ciphertext and plaintext
typo in eqn. 3
Dec
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answered Can you help me with this DES variant analysis?
Dec
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revised Find the key to a Vigenère cipher, given known ciphertext and plaintext
edited tags, copyedit, better title
Dec
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answered Find the key to a Vigenère cipher, given known ciphertext and plaintext
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revised Regex searchable word list for space-less monoalphabetic substitution
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Dec
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comment Perfect secrecy over Stirling numbers
Ps. Also, yes, if $k$ is uniformly distributed over $\{0,1\}^n$ (i.e. "perfectly random"), then $k' = c_1 \oplus m_1$ $= k \oplus m_0 \oplus m_1$ (where $m_0, m_1 \in \{0,1\}^n$) is also uniformly distributed. This follows easily from the observation that the map $x \mapsto x \oplus m_0 \oplus m_1$ is invertible (and, in fact, its own inverse) on $\{0,1\}^n$.
Dec
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answered Perfect secrecy over Stirling numbers
Dec
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answered Regex searchable word list for space-less monoalphabetic substitution
Dec
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comment Does it make sense to stretch non-keys?
@Andrew: "pseudorandom key". It's basically what the HKDF standard calls the output of the first KDF stage. It's not a particularly informative name, but I figured I'd follow their example, since I couldn't think of anything better either.
Dec
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answered Does it make sense to stretch non-keys?
Dec
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comment Regex searchable word list for space-less monoalphabetic substitution
You know, regexps are pretty useful for many things, but not too often for cryptanalysis. I'm somewhat reminded of that silly Jamie Zawinski quote here...